Self-interlocking keyboard

ABSTRACT

A keyboard having magnetically actuated reed switches and interposers swingable between the switches and adjacent magnets for opening and closing the switches in response to key-operated mechanism. Each interposer is supported from a pair of spaced shafts which constitute a bail assembly, the spaced shafts being operable in rotary fashion about a common center, and toothed racks are carried between the shafts and engageable therewith to provide interlocking means for the keyboard. This interlocking means is of the &#39;&#39;&#39;&#39;non-entering&#39;&#39;&#39;&#39; type realizable by cooperation of the shafts with the racks being slidable therebetween, wherein, with one key depressed, depression of another key tends to restore the first-mentioned key.

\ PATENIEDABB m n INVENTORS PETER HI. DEGRAFF a JAMES w LEE f THEIR ATTORNEYS I 1 SELFJNTERLOCKING KEYBOARD BACKGROUND OF THE INVENTION pression of two keys on a typewriter usually results in jamming the type bars against one another and requires manual separation of the bars before proceeding with the work. Of course, the slide or ball type of interlock has been quite common in business machines wherein depression of any one key causes a connected member to cam between adjacent elements and thus move them apart so that a separate key-connected member could not be forced between other like elements along a line thereof. Such interlocking mechanisms, commonly known as being of the entering type", generally ex-, .hibit an interactive disadvantage wherein by reason of pressure upon a non-depressed key, a depressed key tends to be locked, thereby likewise'tending to inhibit release of the depressed key. In this respect, the entering type of interlock may have a tendency to restrict the operating speed capability and additionally have a higher noise level because of the relative closeness of parts and of the materials used. It is by reason of such complaints that improved designs are being sought to gain advantages over the prior-art keyboards.

U.S. Pat. No. 2,383,260, issued Aug. 21, I945, on th application of John Joseph Kittel, discloses one example of prior art interlock mechanism for preventing operative depression of more than one key lever at the same time. The key lever blocking device is a pivoted line lock plate engageable by the heel of an abutment on the key lever, the plate being rocked 'rearwardly to be disposed directly under the toes of other key lever abutments.

1 US. Pat. No. 2,835,369, issued May 20, 1958, on the application of Charles Schroder, shows and describes another key interlock, including key levers engaging adjacent rockers which are journaled on a common pivot rod, each rocker having lugs projecting right and left, and also overlapping edges engageable by the lugs,

so that, on depression of any one key, oppositelytween, so that only one bar can be operated at any one time.

Each of these prior art examples utilizes interlocking means of the entering type, and all suffer from the stated disadvantages of high noise level and slow response upon key release.

SUMMARY OF THE INVENTION ing structure which is self-operating upon depression of a key without added mechanism of any sort beyond that required to obtain the coded output, such structure being capable of efficient operation withthe contact switches. The coded output information derived from depression of the keys is obtained through the normally opened reed switches which are closed, or biased to an on condition, by a proximally located fixed magnet. Foreach of the switch assemblies, there is provided an interposer of ferrous material and supported from a pair of spaced shafts operable in rotary fashion about a common center, the interposer being.

actuated by key-driven mechanism to 'move into and out of the space between the switch and its magnetto open and close the switch. Presence of the interposer within a majority of the space between the switch and the magnet causes sufficient lines of force of the magnetic field to be shunted away from the reed switch, so that the contacts open. In normal operation of the keyboard, each switch is held open, or of bymeans of its respective interposer being spring-biased into the space between the magnet'and the switch, and actuation of a key will remove, by means of later-described mechanism, the appropriate interposers to cause their corresponding switches to close, whereby an electrical binary output, unique to that key, is generated.

Control of each interposer is provided by transverse bail assemblies .within the keyboard frame :behind the keystem area and above. theswitchmagnet area. Each bail assembly comprises. the pair of shafts disposed about a center of rotation, and mounted on and suspended from each shaft pairis the interposer, which is laterally positioned, so as to align with a respective switch-magnet assembly, there being a plurality of interposer-shaft pair assemblies for actuation of each of the magnetic reed switches. interspersed and arranged among the several bail assemblies and running perpendicular to and between each shaft pair are toothed racks, one per keyboard key. One toothof each rack is arranged to bear upon either the upper or the lower shaft of each bail assembly, so as to provide, upon movement of the rack, positioning of :each bail and interposer to either the switch on or the switch .oft position. At its keystem end, each rack is connected to a bellcrank, which intum is driven by depression'of the key. With such arrangement, depression of a key transfers motion, through the bellcrank and toward the front of the keyboard, of the particular rack associated with t the key, so that the rack teeth cause actuation of the bails and the interposers to condition'the reed switches to the output code selected, by means of the appropriate rack teeth locations for thatparticular key. The electrical binary coded output comprises six binary bits derived for each key by the arrangement of the teeth on the. associated rack.

A complete key-to-key mechanical interlock is generated within and is an inherent by-product of the instant encoding mechanism in the, above-described rack-bail mechanism by virtue of the facts that (d) teeth are provided on each rack so that each and every bail-interposer assembly ispositively actuated toward the appropriate reed switch on" or off" condition for a given key and (b) no two keys derive thereby the same electrical output code, so that, as any two keys are depressed, they will be in mechanical conflict as to the on or off" positioning of at least one bail, and the complete depression of either key or both keys is '5 the outputcode selected; by means of the appropriate rack teeth 50, 51 locations, for that key 12.

A complete key.-tokey mechanical interlockgis provided within the above-described rack-bail mechanism by reason that (a) teeth 50, 51 are pr oyi'de d on each rack 14 so that each bail-interposer assembly is positively positioned with respect to the appropriate reed switch on" or of condition for a given key 12 and that (b) no two keys 12 derive thereby the same output code, because, as any two keys 12 are depressed at the same time, they will conflict as to the on" or off" positioning of at least one bail, and the complete depression of either key 12 or both keys 12 is blocked. The nature of the particular construction and the interlocking action is that of a non-entering" type of interlock whereby, with one key 12 held depressed, pressure on another key 12 tends to restore the first-mentioned'key 12 rather than tending to lock down the firstmentioned key 12. in the illustration of this action, and referring to FIG. 1, the 1 key 12 is shown in a depressed position, with its rack 14 actuated toward the front of the keyboard, and the 3 key 12 is shown in an undepressed position, with its rack 14 in the home position. The interlocking of the parts is realized by means of a lower tooth 51 of the 11" keyrack 14 being in the rear of and engaged with the bail lower shaft 38 thereby holding the bail assembly '16 in off position and an upper tooth 50 of the 3 key rack 14 being in the rear of and engaged with the bail upper shaft 37. This latter condition will normally prevent the depression of the 3key 12. If greater pressure is exerted on the 3key 12 rather than on the1" key 12, the bail assembly 16 will be rotated in a clockwise direction thus returning the 1 key 12 to its home position by means of shaft 38 acting on tooth .51. Likewise, teeth and 51 on theremaining racks 14 are positioned and engaged with the associated bail assemblies 16 to prevent depression of any other key 12 at the same time.

Understandably, if sufficient pressure is exerted on a different key 12, it would tend to restore the depressed key 12 in the manner described above.

Associated with the key-to-key or self-interlocking mechanism is a lock-up feature as shown in FIG. 2, the concept and arrangement being employed during machine operationnWith; the 8" key 12 depressed against the action of a rack restore spring 65 connected between a frame member (not shown) and a finger 66 of the bellcrank 55, a tooth 50 onthe rack 14 engages with the upper shaft 37 of the bail assembly 16 as the rack 14 is being moved to the right, or to the forward part of the keyboard. Each of the racks 14 has a finger portion 67 projecting downwardly at the rear thereof for engaging a blade portion 68 of a lockout slide assembly 69 slidably mounted within the framework of the machine (notshown) and movable up and down by means of bellcrank assemblies 70, which assemblies 70 are actuated through a drive arm 71 connected to a lockout solenoid 72. When any one key 12 is depressed, its rack 14 moves to the front of the associated keyboard, and the finger portion 67 moves in front of the blade portion 68, after which the solenoid 72 is energized toraise the lockout slide assembly 69 and thus trap the portions 67 of all other racks 14 to prevent operation of any other key 12 on the key-board. With the lock-up mechanism actuated, the 8" key rack 14 is locked by reason of the lockout blade portion 68 being in the up position, which receives the finger portions .releasing all the finger portiorisl67.

6 6 7 of all other racks 14, and, in effect, all other keys are locked out. The lockout solenoid 72has a spring' return for moving the slide assembly 69 downwardly and for The geometry of the mechanism. of the instant invention provides additional advantages overprior-art keyboards. For instance, a characteristic of the glassenclosed reed switch 25, which is of primary importance to the design of any mechanismusing it, is the differential" of the switch 25.The differential of a switch is defined as'the difference between the level of actuating force or influence required to activate the switch and the level of reduced actuating force or influence at which the switch is deactivated. In a mechanism which uses permanent magnets 26 for the actuation of glass-enclosed reed switches 25, as in the instant invention, the above-mentioned differential" resolves to a distance of physical movement of the magnet 26 with respect to the reed switch 25 or of an interposer 35 with respect to the reed-magnet assembly. In known prior-art keyboards that use reed switching-devices for generation of output signals, the total magnet or interposer movement, with respect'to the reed switch or reed-magnet assembly, has been equal to or less than the total movement of the actuating key. In the instant invention, the total interposer movement with respect to the reed-magnet assembly is nearly four times the total movement of the actuating key.

Additionally, the extent of the reed switch differential as regards its proportion of total key travel in prior art devices has been from 25 to percent of the key travel, depending upon the exact reed-actuating technique employed. A direct resultof solarge a porportion of key travel in the differential range to total key travel is the need for precise, critical, and expensive adjustment procedures during manufacturing processes to avoid improper code emissions from the keyboard. Contrariwise,due to the large interposer travel relative to key travel of the instant invention, the proportion of key travel in the differential range with respect to total key travel is maintained hereby at less than 15 percent of total key travel; l i I It is thus seen that herein shown and described is a keyboard having interlock mechanism of a "nonentering, or-self-interlocking, type which has ad vantages and features that incorporate optimum human factors of design, that minimize movingmass and the inertial effeetsthereof, and that redueeor minimize noise levels. While only one embodiment has been disclosed for the construction-of the self-interlocking key board, certain variations on the above may occur to those skilled in the art, so it is comtemplated that all such variations having these features are'within the scope of the invention. A l

What is claimed is: H

1. A keyboard comprising a plurality of data keys, a i plurality of code rack members each movable to an actuated position in response to the movement of a corresponding data key, a plurality of code bail assemblies, each assembly comprising a pair of spaced apart connected shafts symmetrically disposed about a center of rotation and transversely mounted adjacent said rack members andeach bail assemblybeing rotatable between a first and a second control position,

switch means responsive to the respective control poto operation of the keys, the interlock comprising a plurality of rotatably mounted bail assemblies posi-.,

tioned adjacent to and extending in a direction transverse to the movement of the racks, each of said bail assemblies including a first shaft disposed over said racks and a second shaft spaced from and connected to said first shaft and disposed under said racks,

means engaging'said bail assemblies for normally urging the bail assemblies to a home position, and actuating means including abutment teeth mounted means normally urging each of said bail assemblies to said first control position, and 10 abutment means mounted on the upper and lower sides of said rack members for engaging said spaced shafts upon movement of said rack member to an actuated position, said abutment means posion the upper and lower sides of said racks and positioned to engage said first and second shafts upon movement of the rack in response to the operation tioned to rotate at least one of said bail assemblies of the keys, said actuating means teeth spaced to said second control position whereby the dispoalong said racks and positioned to rotate selected sition of said one bail assembly in said second conbail assemblies to an actuated position against the trol position will prevent depression of two data action of said urging means whereby the bail askeys simultaneously. semblies in said actuated position will prevent de- 2. An interlock mechanism for a keyboard having a pression of two data keys simultaneously. plurality of data keys, and racks movable in response United States Patent .1191

OTHER PUBLICATIONS lBMTechnical Disclosure Bulletin, Variable Left Hunt et al. Aug. 7, 1973 1 1 CARRIER POSITIONING AND TABULATION Margin With Counter Control, Hobgood et al., Vol.

APPARATUS 10, No. 2, July 1967, pp. 109-110 [75] Inventors: Ronald E. Hunt, 'Austin, Tex; IBM Technical Disclosure Bulletin, Printer With Joleph S. Morgan, Lexington, Ky. High-Speed Space Control", H. C. Tanner, Vol. 12,

e No. 12, May 1970, pp. 2260-2261 [73] Asslgnee: g IBM, Technical Disclosure Bulletin, Velocity and Deorpontm celeration Sensors", Amos et al., Vol. 9, No. 12, May [22] Filed: Dec. 28, 1970 1967, pp. 1708-1709 [21] Appl. No.: 101,703

Primary Examiner-Ernest T. Wright, Jr. v A11 --H f d] dJ. H.B kdl 52 us. c|...... 197/176, 197/179 m mm s a e [51] Int. Cl B4lj 25/18 01 Search 1 1 1 82, R, 197/84 A, 84 8,90, 176, 177, 178,179,187 l A carrier positioning and tabulation apparatus includ- [56] 1 Relerences Cited ing a carrier, a leadscrew for controlling carrier ad- UNITED STATES PATENTS vancement, an emitter wheel associated with the lead- 3,346,091 10/1967 Cralle et al. 197/176 screwhavillg and a Spoke 3,315,776 4/1967 Barkdoll et a1. 197/176 x a P devlce associated with the leadscrew for p- 971,696 10/1910 Silvertsen et a1. 197/179 p s rotation of the leadscrew and advancement 9f the 3,121,487 2/1964 Gassino 197/176 carrier, and a pin wheel rotatable synchronously with 3,137,381 6/1964 Behr et a1. 197/179 X advancement of the carrier and having settable pins for 3,233,372 Ffechemn- 197/179 X indicating the approach of a tabulation position which 33931092 2/1970 97/176 is defined by a signal generated upon the sensing of the 3,512,137 5/1970 Jones et al. 197/84 R X home emitter spoke 3,572,489 3/1971 Schaefer [97/82 5 Claims, 2 Drawing Figures 

1. A keyboard comprising a plurality of data keys, a plurality of code rack members each movable to an actuated position in response to the movement of a corresponding data key, a plurality of code bail assemblies, each assembly comprising a pair of spaced apart connected shafts symmetrically disposed about a center of rotation and transversely mounted adjacent said rack members and each bail assembly being rotatable between a first and a second control position, switch means responsive to the respective control position of each of said bail assemblies for generating data signals indicative of the data key moved, said switch means including a contact unit, a magnet and an interposing member downwardly supported from said shafts and swingable in an arc between said contact unit and said magnet for actuating said contact unit, means normally urging each of said bail assemblies to said first control position, and abutment means mounted on the upper and lower sides of said rack members for engaging said spaced shafts upon movement of said rack member to an actuated position, said abutment means positioned to rotate at least one of said bail assemblies to said second control position whereby the disposition of said one bail assembly in said second control position will prevent depression of two data keys simultaneously.
 2. An interlock mechanism for a keyboard having a plurality of data keys, and racks movable in response to operation of the keys, the interlock comprising a plurality of rotatably mounted bail assemblies positioned adjacent to and extending in a direction transverse to the movement of the racks, each of said bail assemblies including a first shaft disposed over said racks and a second shaft spaced from and coNnected to said first shaft and disposed under said racks, means engaging said bail assemblies for normally urging the bail assemblies to a home position, and actuating means including abutment teeth mounted on the upper and lower sides of said racks and positioned to engage said first and second shafts upon movement of the rack in response to the operation of the keys, said actuating means teeth spaced along said racks and positioned to rotate selected bail assemblies to an actuated position against the action of said urging means whereby the bail assemblies in said actuated position will prevent depression of two data keys simultaneously. 